1. Obviously, record his name and age.
2. Record the date, time and location of the event.
As far as questions to make it interesting.
1. Did you expect the flood to happen? / Did you expect the flood to be as bad as it was?
2. What was your reaction when the flood hit? Were you at home?
3. Did you manage to salvage anything in the flood?
4. What got destroyed in the flood?
5. What was it like going home and seeing that all your belongings had been destroyed?
6. What are your next steps? Do you plan to rebuild?
7. What words of encouragement can you give to other flood survivors and their familie